1. Field of the Invention
The present invention relates to a method of bleaching sulfonic acid by the use of a bleaching agent consisting of peroxide and water in the presence of aliphatic alcohol having 1-12 carbon atoms and under acid condition.
2. Description of the Prior Art
There are known varieties of methods for bleaching sulfonic acid under acid condition. For instance, British Pat. No. 983,056 discloses a method of bleaching with hydrogen peroxide, sodium hypochlorite or the like before or after hydrolyzing .alpha.-olefin sulfonate, and Japanese Patent Publication No. 956/1966 discloses a bleaching method comprising the process of bleaching a highly colored sulfonic acid with hydrogen peroxide, neutralizing thereafter and bleaching again with hypochlorous acid or the like.
According to these known methods of bleaching, however, a satisfactory result cannot be expected in the case of sulfonic acids that are highly colored and hard to bleach, because a large quantity of bleaching agent is added, the effect obtained by adding a large quantity of bleaching agent is not sufficient, and a deterioration of the color takes place with the passage of time.